The invention discloses a processing method of a steel structure conveying rack for rapid object truck loading. The processing method comprises the following steps: step one, erecting supporting devices, and installing automatic turntables at the tops of the supporting tables; step two, placing a main workpiece of the steel structure conveying rack between the two supporting pieces, and fixedly assembling the two ends of the main workpiece on the automatic turntables; step three, assembling the main workpiece totally; step four, welding and fixing the assembled main workpiece by a welding machine, and simultaneously welding on the front side and the reverse side through the rotating matching of the two automatic turntables; step five, checking whether the welding quality is qualified, if yes, obtaining the steel structure conveying rack, if not, carrying out the step four continuously. The processing method effectively solves the problem that the workpiece is difficult to turn over during welding on the front side and the reverse side, and is simple and convenient in operation, safe and reliable, thus greatly improving the processing efficiency and ensuring the processing quality of the steel structure conveying rack.